Piston ring



April 27, 1937. F. A, LUTHY 2,078,394

PISTON RING FiledApril l0,` 1956 Patented Apr. 27, 1937 UNITED sTATEs PATENT oFFlcE rIs'roN me Fredrick A. Luthy,` Jackson, Mich. y Application April 16,1936, serial No. tassi 1 claim.

The present invention relates to improvements in piston rings for internal combustion engines and the like and has particular reference to a split oilv ring employing an in ner expander 5 spring. 4

Heretofore in commercial practice it has been known to insert an irregular shaped expander spring between the oil ring and the bottom of l the ring groove in the piston. In such constructions the oil ring has been provided with radially extending ports spaced circumferentially of the ring through which oil is adapted to flow and ports are provided in the vertical wall of the groove opening into the interior of the piston. In order to assure the passage of oil through the ports in the ring and those of the groove past the imposed spring, notches and apertures have y,

been provided in the spring, which is usually of at wire stock. 'I'he employment of these notches and apertures not only lessens the tension of the expander spring but tend to apply an olif-center thrust upon the oil ring which cocks or tilts the same in its groove greatly impairing the eillciency thereof.

It becomes an object of the present invention to provide a piston ring of a. construction which will maintain the expander spring in a centered position and the ring at all times will be under a uniform radially directed thrust without any tendency of cooking or tilting in the ring groove.

Another object isv to provide an oil ring having radially extending ports circumferentially spaced in which the ring construction defining the portsis such as to eliminate clogging due to particles of foreign carbon and other matter v in the oil 'and the ports are substantially selfcleaning.

Another object of the invention is to provide an oil ring and inner expander spring assembly 40 oi! .a construction which results in the expander spring and ring being maintained in a denite relationship within the ring groove and clearances are provided and maintained between the spring and groove which provide adequate pasv sage for the new of oil between the ports of the ring and the ports of the groove without modifying the spring construction in any manner such as by providing notches or apertures therein.

A. further object is to provide an oil ring and inner expander spring assembly in which provision is made for maintaining during operation adequate passage for flow of oil radially and circumferentially of the ring groove.

These and other obiects residing in the speciiic details of construction will through the passages I8. This become apparent upon the consideration of the following detailed description when considered in connection with the accompanying drawing wherein,

Fig.f 1 is a fragmentary side elevational view 5 of a 'piston partly shown in cross-section showing the improved oil ring in position,- and Fig. 2 is a plan view showing the parts of the improved oil ring in assembled relation.

The piston I0 is shown with conventional 10 compression ring grooves I2 and I3 having cornpression rings I4 and I5 therein andan oil ring groove I6 into which passages I8 open through the Walls of the piston for, removal of oil from the oil groove I6 through the interior of the pis- 15 ton in awell known manner. As shown my improved oil ring comprises anouter ring 20 having circumferentially spaced openings 22 for the removal of oil from the cylinder wall. 'The innersurface of the Ying' 20 is recessed providing a 20 pair of converging conical seats 24 and 26 extending circumferentially of the Vring 20.

An expander spring 28 o! wire stock and of well A known conguration is inserted between the wall 30 of the groove I6 and the ring 20 and engages 25 at vertically spaced points its outer periphery with the conical seats 24 and 26. The spring 28 which is preferably of considerably less widththan the ring 20- is centrally maintained within the groove I6 by the inclination of thetconverg- 30 ing seats 24 and 26. With4 the spring thus centrally positioned within the groove I6 circumferentially extending oil passages 32 and 34 are defined between the spring 28 and the upper and lower walls 36 and 30 of the groove I6. The 35 oil removed through the openings 22 may circulate circumferentially of the piston through the passages 32 and 34v vbefore being discharged arrangement overcomes any tendency for a'particular arc of 40 the oil ring being unable to remove an unusual amount of oil from an area of the piston wall receiving an excessive amount of oil as the oil being removed is freely distributed circumferentially ofthe oil groove and need not be en- '45 tirely removed through the passages I8 directly opposite such area. Another decided advantage resulting from centrally locating the expander spring resides in uniform'radial expander action upon the outer ring 20 and any tendency for cooking and irregular wear that might result from an oil-center application of action is eliminated. Moreover, with a'narrow centrally maintained' expander spring no apertures, notches, or

the like, need be provided in the spring for avoiding objectionable restriction of oil flow.

In addition to the centering action of the recessed inner surface of the ring 20, another decided advantage of construction is obtained, namely, the openings 22 are less likely to become clogged with foreign matter than in an oil ring of conventional construction in which the inner and outer faces are parallel. This characteristic is attributed to the decreased depth of the ring 20 at the central ported area and the are of the wall structure dening the inner ends of the openings 22.

While in the illustrated embodiment of the invention I have shown the oil ring 20 with a V- shaped recess deiined by the converging conical seats 24 and 26, I wish to include as part of 'this vinvention other obvious forms of construction capable of functioning equally as well to urge the expander spring by its own expanding action to a denite seat or position with reference to the outer ring and/or the ring groove. In this respect the invention includes the employment of one or more surfaces inclined to the radial ex# panding action of the expander spring for deilnitely positioning the same. Moreover, the invention is not limited to oil rings as it is of equal importance in a compression ring that the expander spring act uniformly.

I-Iaving described my invention what I desire to protect by Letters Patent and claim is:

An oil ring and expander assembly of a design to be used for the removal of oil from the cylinder walls and to drain the same through ports in the oil ring groove of the piston for return to the sump through the interior of the piston comprising an oil ring to be located in a ported groove of a piston having circumferentially spaced radially extending ports centrally positioned therein, the inner surface of said oil ring being sloped inwardly in opposite directions to form a substantially V-shaped groove into which said radially extending ports open to provide a aring discharge at the inner ends'of said ports, an expander spring of less width than said oil ring and adapted to engage with the sloping sidesof said V-groove-at points spaced above and below said radially extending ports when said ring and expander are positioned in an assembled relation in a ported piston ring groove, said spring being of angular configuration so as to engage with said V-groove only at circumferentially spaced points, the expanding action of said spring in said V-groove resulting in said spring centering itself when in use spaced from the bottom and top of the ring groove to permit oil to ow between said ports in the piston and the ports in said ring and around the spring without obstruction as well as providing circumferential oil passages above and below said spring, the axial dimension of said radially extending ports being substantially one-third the axial width of said oil ring, the solid portions of said oil ring disposed between said ports and said ring being sufficiently close together as to restrain any axial deflection of portions of said oil ring under the action of said spring.

FREDRICK A. LUTHY. 

